Improvement in apparatus for collecting precious metals



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Janes r. MCDOUGALL; or sAN tennessee,CALIFORNIA.

Letters Patent No. 109,533, dated'November 22, 1870.'`

IMPROVEMENT IN APPARATUS FoR ooLLscTiNGPRi-:cious,METALs.

The lSchedule referred to in these Letters Patent and mail-Ling .part of the same.

To all whom, it may concern..- l

Be it known that I, J AMES T. MGDOUGALL, ofthe city and county of'San Francisco, State 0f California, have invented an improved Apparatus for Collecting the Precious Metals; andI do hereby declare the following description au accompanying drawing are sufiicient to enable any person skilled iu the art or science .to which it mostnearly appertaius, to make and use my said invention' or improvement withoutfurther invention or experiment.

My invention relates to imgrovements on an improved method of collecting the' precious metals, for which Letters Iatent were granted to me, No. 73,021, dated January 7,1868, and No. 83,8158, dated Norveinber 10, 1868. f v

` V'My formeriiiventions contemplated'the use ot' metallic standards, either separately or united in sections, placed in an ordinary sluice, the bottom of which had previously becn covered with one armere amalgam ated plates.

The standards were more particularly described as being composed of copper and iron, by which combination' of metals a retaining amalgamated surface was pi-esented, and an electrical action was induced, which 'would serve to collect and precipitate even the tinest particles of gold or other metals, (see patent No. S3,-

ses.

.metal are precipitated without the. electrical influence and hii'dly, coating or covering the metallic plate form? ing the bottom ot' the sluiec with gold or silver amalgam, oi the amalgam of some ofthe base metals, in order to give a heavier body ot' Quicksilver with less fluidity.

In order to explain my iuveiition so that others will be able to understand its construction and operation,. reference is had to the accompanying drawing forining a part of this specilication, in which- A A represent the two sides of an ordinary shnce,` and B the bottom.

As before stated, my inventions, as covered by former patents, contemplated the employment ot' hollow metallic standards, siinilar4 to G,pla`ced vertically in the sluice, having slotted sides, through which the water communicatedv with the interior, which was prof vided with amalgamated copper slips or bars;

The hollow standards G maybe made singly or otherwise, as desired, but I prefer to make them in sections of four, as shown at Figure l, and connect them together by an open frame-work or metal plate, I), which is provided with piojecting'-corners et a.

In order to secure the copper in the hollow standards, I take either strips which shallviit against each side ofthe square hole which passes through the standards, or use pieces of copper of sonic other convenient torni, and, after properly placing them, drive into the hole a'plug or center ot' dry wood, E, which presses the copper firmly against the iron.

When the stainlardsare placed in `the water theA wooden plug Ekwill swell, as it becomes saturated, so as to hold the copper in contact with the iron with kgreat firmness, and'thus exclude the air and preventoxidation on the inside ofthe tube, while sucicnt moisture is admittedto sustain chemical action between the metals, by this means causing the exhaustion to take ilace' on the outer surface of the ehea er nietal.

Incase iron and copper are not used, other combi-- nations ot' metal, capable ot accomplishing the saine result, can be substituted for them.

Either en d ot' the set may rest upon the bottom of the sluier, and the riti-les or standards are always placed in straight lines across the sluice. With the square ot the tube diagonal to the course of the running stream, thi-ec lines ot' discharge or passages are presented at the saine time, radiating from the same point, as shown by the arrows, Figure f?,V

'Ihe etl'ect ot this peculiar arrangement of the stainlards is to give a side-to side rocking or wave-like inotioii to the moving water, which not only l'cta'rdslits downward movement, but also holds the solid particles suspended, thus permitting them to settle iu order, according to their specitic gravit-ies. v -Y This roel-:ing or wave-like motion is not unlike that produced bythe ordinary hand-rocker used in mining,

and this, together with the electrical charge and lthe numerous eddies created by thek vertical riiiies, serves to precipitate the intinitcsimally-small particles vot' metal with a certainty -and success heretofore 4nnknown. y

For some kinds of mining, and where thecircuni-` stances of the case will 'not justify the expense of metallic ritlles,- I use square wooden' bars, E, or bais or 'obstructions ot' some other cheap metal or substance,

which may also be a composition of various substances. In any case, their arrangement inthe sluice should be according to the plan above described, so as to produce-the saine rocking elcct.

1 In this case the obstructions may rest ou amalgamated metallic plates, or mercur or amalgam may be retained on the bottom of the sluice by any ordinary rifliing, or they may be used without mercury, the

particles deposited being collected in the usual manner.

In the use of my metallic riies, I prefer wooden sluice-boxes with bottom and two sides, made in the usual way, because of its cheapness; yet, many other substances, such as metal, ce|nent,'or stone, may be used, as circumstances require.

The bottom of my sluice-box is usually coyercd with -sheets of copper, or other metal having ainity for mercury, but also having a lleavydeposit of the amalgam of .mercury and gold, or mercury and silver, or an amalgam of mercury and some of the base metals, which it is important to keepin a soft pasty condition by the occasional addition ot' mercury, as it will harden by the absorption of the precipitated particles of metal.

Having thus described my. invention,

What I claim, and desire to secure by Letters Patent. is-

1;. The wooden bars or centers E, substantially as and for the purpose above described. I

2. The standard F, constructed as described, forthe purpose of giving the wave-like or rocking motion to the water, as above specified. v

43. In combination with the standards 0r obstruc- ,tions C or F, the copper bottom B with a soft amalgam of gold or silver, or some ofthe base metals, substantially as andfor the purpose set forth.

In witness whereof I have hereunto set my hand and seal.

JAMES T. MCDOUGALL. [n s] Witnesses:

G. FITZGERALD, WM. R. BOONE. 

